This is a longitudinal, observational study, which does not include any intervention. There are three study groups. The first group consists of BLSA participants without known coronary disease; the second consists of individuals with a coronary artery calcium score less than the 25th percentile for their age and gender; the third group consists of individuals with premature coronary artery disease (diagnosis made at age <60 in females and <50 in males) or with a coronary calcium score which is greater than the 50th percentile for their age and gender. Participants in the second and third group listed above are recruited from the Johns Hopkins Medical Institutions. Recruitment into these groups has been on or ahead of schedule, and we are ready to begin the longitudinal component of the study. Recruitment into the first group is performed at the National Institute on Aging. The past year saw a marked improvement in our ability to recruit these volunteers, and we have now completed all first visits and are now completing the second visits of all participants. Analysis of the first visits is being conducted to assess cross sectional findings which can then be expanded to a longitudinal analysis once all second visits are completed.